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Neutron depth profiling (NDP) is a non-destructive analysis method which is widely used in lithium batteries, semiconductors, and other complex and high-precision industries. The NDP spectrum is the second particles of the interaction between neutrons and target nuclides, and then the content and spatial information of the target nuclides in the measured samples are obtained by unfolding the NDP spectrum. At present, the common NDP spectrum unfolding algorithm is the maximum likelihood expectation maximization (MLEM) algorithm. But in some case, the MLEM algorithm falls into the local optimal solution. In this paper, a hybrid PSO-MLEM algorithm by taking advantages of the wide search range of PSO (particle swarm optimization) and the fast convergence speed of MLEM was proposed. In the PSO-MLEM algorithm, the dynamic acceleration factor was used to balance the local optimal and the global optimal on the particle displacement in each iteration, which improved the convergence speed and the accuracy of the algorithm. The PSO-MLEM algorithm was applied to unfold the NDP spectra of lithium batteries with 0, 5, and 10 hours of charging and discharging, which were simulated by Geant4 tool. The unfolding results of PSO-MLEM algorithm were compared to the results of PSO algorithm, MLEM algorithm and singular value decomposition solving least squares (SVDLS) algorithm. The correlation coefficients of the unfolding result by PSO-MLEM algorithm and the reference distributions are 0.993, 0.984, and 0.946, respectively, and the relative average errors are 14.46%, 9.84%, and 9.41%. Compared with PSO algorithm, the convergence speed of PSO-MLEM algorithm is improved from 800 times to 100 times, and the relative error is reduced from about 50% to about 10%. To the MLEM algorithm, the PSO-MLEM algorithm improves the global optimization capability and avoids the problem of local optimal solution caused by the influence of the initial value of the MLEM algorithm, especially with the result of 0 hour. The SVDLS algorithm is worked well in unfolding NDP spectra except the NDP spectrum of lithium battery at 0 hour. Compared to result of SVDLS algorithm, the PSO-MLEM algorithm has better convergence properties and is numerically stable.

Objective: To obtain cancer stem cells (CSCs) from surgically resected colorectal cancer specimens and identify their stem cell characteristics., Methods: Colorectal cancer tissue specimen obtained from a patient undergoing radical resection of colorectal cancer were implanted in nude mice, and the xenograft was harvested 1 month later to obtain purified tumor cells by enzyme digestion and adherent culture. The CSCs were screened by limiting dilution method and serum-free culture to identify their phenotypes. Soft agar colony assay was used to assess the proliferative ability of the CSCs and human colorectal cancer cell line SW480. The tumorigenic ability of the isolated CSCs and SW480 cells was evaluated by observing their subcutaneous tumor formation in nude mice. Western blotting and immunofluorescence assay were used to detect the immunophenotype of the CSCs and SW480 cells., Results: The primary cultured CSCs from clinical specimens of colorectal cancer underwent differentiation in the presence of serum in the culture. Soft agar colony formation assay showed that the CSCs had a colony formation rate above 50%, significantly higher than the rate of colorectal cancer SW480 cells (4.41%; P < 0.01). In nude mice, subcutaneous injection of 500 CSCs was sufficient to result in subcutaneous tumor formation, while the injection of 500 SW480 cells failed to form any subcutaneous tumors. The CSCs expressed CD133 and CD44 but not CK7, while SW480 cells expressed CK7 but not CD133 or CD44., Conclusions: CSCs can be derived by primary culture of cancer cells obtained from surgically resected colorectal cancer tissue followed by serum-free culture, and the CSCs obtained have self-renewal and differentiation abilities.

Weizhou Island (109 degrees 00'-109 degrees 15'E, 21 degrees 00'-21 degrees 10'N) locates in the north coral reef distribution belt of the South China Sea. In such relatively high latitude area, sea surface temperature (SST) is an important factor affecting the development of coral reef ecosystem. Measurements of the latest 42 years' SST of Weizhou Island showed that with 3-4 years and 7-8 years fluctuating cycles, the SST almost had a synchronous increase with global warming, especially since the later 1980s. Overall, the coral reef of Weizhou Island could benefit from the SST warming, especially the cold months SST increase, because it's the north margin of tropical zone. But, the warming of the warmest month may be a thermal stress on the development of coral reef. It reaches the upper limits of coral reef development, and leads the coral reef bleaching. Mankind activities, including wide scale building, oil gas factory near the island, traveling, fishing and breeding, may be also the potential stresses on limiting the coral reef development. The combination of summer warming and mankind stress is possibly to destroy the coral reef ecosystem of Weizhou Island. Based on a detailed field investigation, the modern coral reef distribution map around Weizhou Island was described.

Background: To investigate the relationship between progressive development of mouse pulmonary tumors and expression of cell surface saccharide and to provide a theoretical basis for diagnosis of pulmonary benign and malignant lesions.., Methods: A/J strain mice at 5 weeks of age were treated intraperitoneally with 20-methylcholanthrene, and 292 pulmonary lesions including 237 benign lesions (hyperplasia, alveolar adenoma, and papillary adenoma) and 55 malignant tumors (papillary adenocarcinoma) were obtained. The binding affinities of cells in normal respiratory epithelia and various proliferative lesions to four peroxidase-conjugated lectins, Maclura pomifera agglutinin (MPA), Arachis hypogea agglutinin (PNA), Ricinus communis agglutinin (RCA), and wheat germ agglutinin (WGA) were examined., Results: Cells of hyperplasias and alveolar adenomas showed fairly strong affinities to all the lectins. However, most of papillary adenoma cells and papillary adenocarcinoma cells lost their binding affinities to MPA, PNA, and RCA, but not to WGA. Between the benign and malignant lesions, there were significant differences in binding affinities of cells to MPA (Chi-square =46.89,P < 0.01), PNA (Chi-square =36.77,P < 0.01) and RCA (Chi-square=52.87,P < 0.01), but not to WGA (Chi-square=0.09,P > 0.05)., Conclusions: According to the different complex glycoconjugates on cell surface of various pulmonary lesions, the binding affinities to MPA, PNA and RCA are quite different between the benign and malignant lesions. The detection of bindings is helpful to the differential diagnosis of the pulmonary benign and malignant lesions.